1. Field of the Art
The present invention relates generally to a utility power line safety and maintenance device. More specifically, but without limitation, the present invention relates to a quick release device for connecting power lines often at or near junctures such as utility poles.
The occurrence and costliness of severe weather events have increased in the last few decades. Nine of the top 10 costliest hurricanes to hit the U.S. mainland occurred in the last decade. In October 2012, Hurricane Sandy's violent winds damaged thousands of utility poles and left more than 8.5 million people without power (U.S. Department of Energy, 2012). To respond, the Southern Pressure Treaters' Association (“SPTA”) shipped 65,100 wood poles and 103,500 cross arms. However, the total number of utility poles repaired is slightly higher than this since several wood pole providers in the United States are not members of SPTA.
Over a six week period in 2004, four hurricanes struck Florida, damaging 3,000 miles of power line, 32,000 utility poles, and 22,000 transformers. In 2008 when Hurricane Ike struck the gulf coast of Texas with 110 mph hurricane winds, the result was 2.15 million households without power.
Hurricane Katrina in 2005 resulted in 1.7 million people without power. Power outages and other damage caused by these storms are not only costly; they are also very time consuming. Rodney Walter, Senior Engineer: Planning & Reliability at Indiana Michigan Power, a unit of American Electric Power, estimates that the cost to replace a single utility pole is $3,200 and takes a crew approximately 4 hours to replace, depending on the accessibility of the location. However, the economic cost of not restoring power quickly is much higher.
For some utility companies, restoration costs exceed net operating income for the year. From 1994 to 2004, utility companies spent $3 million per day, on average, to repair systems following a major storm. However, the economic impact of an area or city functioning without electric service for any number of days is far greater than the cost of repairing the damage. Because of this, utility companies incur additional costs to request outside aid and restore power as quickly as possible.
Increasing restoration costs also result from population increases as utility companies expand systems to serve the new customers. Because the power lines and utility poles of the distribution system are frequently damaged or knocked down during a severe weather event, a method allowing for graceful degradation of the distribution system and/or components that minimize impact and enable fast recovery is desired. Currently, power restoration efforts consist of repair workers replacing damaged utility poles and repairing power lines. The proposed Quick Release Connector interfaces with the existing distribution system to reduce excess loading forces on a utility pole, preventing damage to the pole and power line and allowing rapid power restoration.
2. Description of the Prior Art
Several prior art solutions have been proposed to address the problem of downed power lines. However, none of the known prior art solutions is as effective at interfacing with the existing distribution system to reduce excess loading forces on a utility pole, thereby preventing damage to the pole and power line and allowing rapid power restoration.
U.S. Pat. No. 3,711,049 discloses a limiter fixed at one end to a power line tower, or pole arm, and at the other to an insulator attached to a power line. Movement of the line beyond a predetermined limit in either direction causes the limiter to release the insulator, dropping the line and preventing damage to the tower. In one modification, angular movement of the insulator upsets a toggle held in position by a latch in such manner that a cam surface attached to the insulator lifts the latch as the insulator pivots beyond a predetermined angle. The cam shape determines the angle which causes unlatching. In another modification, the horizontal component of the force on the tower is resisted by a spring-loaded lever system; and when the force exceeds a predetermined amount, the spring releases the lever system and the insulator is released.
U.S. Pat. No. 3,761,865 discloses a breakaway connector attached to a pole to release a cable supporting electrical wires extending to a building upon excessive pull on the cable, caused by high winds, ice accumulation, accident or the like. A disconnect is provided in each of the electrical wires adjacent the pole so that the wires will be disconnected when the cable is released, thereby preventing charged electrical wires from lying on the ground. The breakaway connector includes a pivotal detent bar which is longitudinally shiftable towards the cable against the bias of a relatively heavy compression spring. The cable is connected to the detent bar by a ring looped over an upright portion of the bar. Cable tension on the ring tends to both rotate and longitudinally shift the bar. Under normal cable load conditions, the bar engages stop means to prevent its rotation; however, excessive pull on the cable longitudinally shifts the bar away from the stop means to allow its rotation which, in turn, releases the ring and cable from the detent bar. Each disconnect for a wire includes a female clip having a socket and a male clip having a stub which is split longitudinally and is provided with pipe threads, on the inside, while an Allen screw for adjustment along the threads adjusts the friction fit between the stub and the socket. A plastic cover which extends beyond each clip and protects the connection from weather is attached to the female clip, so that it will remain with the female clip, when the clips separate. This prevents a short between the female clips of several disconnected wires, after separation.
U.S. Pat. No. 4,195,192 discloses a safety disconnect switch for mounting on a utility pole to serve as an anchor at one end of a suspended service entrance cable extending to a remote building, so as to first disconnect the cable and then drop it harmlessly to the ground upon an excessive tension force being applied to the cable by a falling tree or the like. This device includes a movable terminal clamping means or slider that joins the terminal ends of the wires of the suspended cable to the bus bars of the incoming power supply lead wires. A detent switch mechanism or means holds the movable terminal clamping means in either a first fixed position or a second cable-released position. The detent switch means also includes a locking means and a trigger means to open the locking means upon a predetermined tension force being exerted on the suspended cable.
U.S. Pat. No. 5,011,437 discloses a connector for connecting an electrically conductive cable to the terminal post of a wet-cell storage battery in such a manner as to facilitate quick connection and disconnection therebetween.
U.S. Pat. No. 5,315,064 discloses a suspended line cable breakaway device including a first body portion for connecting to a first end of a support cable and a second body portion for connecting to a second end of the support cable. The first body portion includes resilient fingers having nubs, which are releasably received by slots contained in a cavity wall of the second body portion. A biased spreader, slidably contained in a cavity in the second body portion, is displaceable axially along the cavity by an external force along the support cable to urge the nubs outwardly such that the second body portion is disengaged from the first body portion, simultaneously disconnecting component lines of a first end of a suspended line from corresponding component lines of a second end of the suspended line. A shield protects the component line connections, which are spaced internal to the device, from the elements. One embodiment provides a breakaway device for a three-component line and a first modified embodiment provides a breakaway device for a four-component line. A second modified embodiment provides a breakaway device without internal component line connections.
U.S. Pat. No. 5,581,051 discloses an insulating assembly for an overhead power line having a main subassembly formed of two parallel spaced insulators joined at their ends by aluminum end pieces. The end pieces each have a slot aligned with the space between the two insulators and a rod projecting from the end piece in alignment with the slot but below the slot. This arrangement enables the subassembly to be hung on a hot power line with the line passing along the slots and the space between the insulators. The rods may be clamped to the line by any suitable device such as wedges and C-shaped clamps. With the subassembly thus mechanically and electrically connected securely to the line, the line can be severed at a location between the end pieces and the free ends forced apart.
U.S. Pat. No. 5,789,700 discloses a grounding device for positively grounding a broken electrical conductor has a primary body having a mounting post extending therefrom. A bracket is fixed to the pole carrying the conductor, and a clamp connects the mounting post to the bracket. To raise the grounding device, an extension bracket is fixed to the bracket, and the grounding device is clamped to the extension bracket. A secondary body is rotatable with respect to the primary body. A spring-urged tongue carried by the primary body is held in place by hooks on the secondary body; so, when the secondary body is rotated, the hooks are moved, and the tongue is projected from the housing.
U.S. Pat. No. 5,942,723 discloses an isolating switch for an electric power line including a sub-assembly made up of two electrically conductive and pieces interconnected by at least one insulator. The end pieces have respective aligned grooves for registry with the electric power line, and securing members for permanently securing the end pieces to the electric power line. The sub-assembly is provided with two keeper bars for mounting the sub-assembly to the power line prior to permanently securing the end pieces to the power line. Each of the keeper bars is pivotally mounted on a respective one of the end pieces and is pivotable manually between a first position in which the keeper bar is completely clear of the groove and a second position in which the keeper bar extends across the groove to retain the sub-assembly on the power line. A detent member is provided on each end piece for cooperation with the respective keeper bar, and a spring member urges the keeper bar and detent member into mutual engagement when the keeper bar is in the second position to retain the keeper bar in the second position.
U.S. Pat. No. 6,062,915 discloses an electrode connector for securely holding a thin flexible electrode. The electrode connector includes a bottom jaw member and an upper jaw member that are selectively movable between an open position and a closed position. The upper jaw member and the bottom jaw member are biased into a closed position. The electrode connector includes an electrical contact assembly configured to provide electrical contact with the flexible electrode. The electrical contact assembly comprises a contact platform and a contact pin attached thereto. The contact platform is configured to form an electrical contact with the contact area of the flexible electrode.
U.S. Pat. No. 6,851,262 discloses a tool for securing a connector on a conductor using an explosive charge includes a first tool member and a second tool member movably mounted on the first tool member. A breech chamber is defined in at least one of the first and second tool members. The breech chamber is adapted to receive the explosive charge. A breech opening is defined in at least one of the first and second tool members and communicates with the breech chamber. A drive member is provided. The tool is adapted to forcibly move the drive member responsive to an explosion of the explosive charge in the breech chamber. The second tool member is movable between a closed position, wherein the breech opening is closed, and an open position, wherein the breech opening is open to allow loading and unloading of the explosive charge into and from the breech chamber, by sliding the second tool member relative to the first tool member along a slide axis and additionally pivoting the second tool member relative to the first tool member about a pivot axis transverse to the slide axis.
U.S. Pat. No. 7,164,079 discloses an overhead service drop extending between a utility pole and a customer location including at least one power conductor, a neutral conductor messenger supporting itself and the power conductor, and a separable power connector between the power conductor and a corresponding utility power conductor adjacent the utility pole. The overhead service drop further includes a separable neutral connector between the neutral conductor messenger and a corresponding utility neutral conductor, and a mechanical breakaway member between the neutral conductor messenger and the utility pole. The mechanical breakaway member breaks away prior to breakage of the neutral conductor messenger to permit preferential separation of the separable power and neutral connectors based upon increased tension imparted to the neutral conductor messenger by a falling object.
U.S. Pat. No. 7,300,301 discloses a quick-release conductor head for engaging a conductor, but capable of quickly releasing the conductor, if necessary. The quick-release conductor head includes a body for receiving the conductor, a latch pivotally connected to the body, a locking system for temporarily maintaining the latch in a closed position, and an opening system for automatically moving the latch from the closed position to the open position. In the closed position, the conductor is maintained within the body, while in the open position the body can be easily disengaged from the conductor.
U.S. Pat. No. 7,943,871 discloses an in-line electrical conductor switch including a frame, an electrical connection section movably connected to the frame, and a rotational stability device. The frame includes first and second connection sections insulated from each other by an electrical isolation section. The first and second connection sections are configured to connect to respective ends of first and second electrical conductors. The switch is entirely supported by the first and second electrical conductors. The electrical connection section is movably connected to the frame between a first connected position and a second disconnected position. The rotational stability device is connected to the frame and adapted to reduce or prevent rotation of the frame about an axis through the ends of the electrical conductors during movement of the electrical connection section to the second disconnected position.
U.S. Pat. No. 8,389,881 discloses a conductor termination system for use with an electrical power transmission conductor includes a termination assembly and a connector. The termination assembly includes an end member and an integral retainer mechanism. The end member includes a receiver portion configured to receive a segment of the conductor. The retainer mechanism includes a moveable keeper member on the end member. The retainer mechanism is operable to selectively clamp a segment of the conductor in the receiver portion to the end member and to apply a retention load to the conductor segment. The connector is adapted to be applied to the end member and the conductor to securely clamp the conductor segment to the end member.
The prior art, however, has failed to fully address the need for a safe, effective, reliable, low cost, system for releasing a power line from a utility pole prior to the power distribution system suffering damage and/or prior to live power lines being pulled to ground level.